The present invention also provides methods of using new and known compounds to inactivate pathogens in health related products to be used in vivo and in vitro, and in particular, blood products.
Although improved testing methods for hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV) have markedly reduced the incidence of transfusion associated diseases, other viral, bacterial, and protozoal agents are not routinely tested for, and remain a potential threat to transfusion safety. Schmunis, G. A., Transfusion 31:547-557 (1992). In addition, testing will not insure the safety of the blood supply against future unknown pathogens that may enter the donor population resulting in transfusion associated transmission before sensitive tests can be implemented.
The recent introduction of a blood test for HCV will reduce transmission of this virus; however, it has a sensitivity of only 67% for detection of probable infectious blood units. HCV is responsible for 90% of transfusion associated hepatitis. It is estimated that, with the test in place, the risk of infection is 1 out of 3300 units transfused.
Further, while more sensitive seriological assays are in place for HIV-1 and HBV, these agents can nonetheless be transmitted by seronegative blood donors. International Forum: Vox Sang 32:346 (1977). Ward, J. W., et al., N. Engl. J. Med., 318:473 (1988). Up to 10% of total transfusion-related hepatitis and 25% of severe icteric cases are due to the HBV transmitted by hepatitis B surface antigen (HBasAg) negative donors. Vox Sang 32:346 (1977). To date, fifteen castes of transfusion-associated HIV infections have been reported by the Center for Disease Control (CDC) among recipients of blood pretested negative for antibody to HIV-1.
Even if seroconversion tests were a sufficient screen, they may not be practical in application. For example, CMV (a herpes virus) and parvo B19 virus in humans are common. When they occur in healthy, immunocompetent adults, they nearly always result in asymptomatic seroconversion. Because such a large part of the population is seropositive, exclusion of positive units would result in substantial limitation of the blood supply.
An alternative approach to eliminate transmission of viral diseases through blood products is to develop a means to inactivate pathogens in transfusion products. Development of an effective technology to inactivate infectious pathogens in blood products offers the potential to improve the safety of the blood supply, and perhaps to slow the introduction of new tests, such as the HIV-2 test, for low frequency pathogens. Ultimately, decontamination technology could significantly reduce the cost of blood products and increase the availability of scarce blood products. Furthermore, decontamination may extend the storage life of platelet concentrates which, according to Goldman M. and M. A Blajchman, Transfusion Medicine Reviews. V: 73-83 (1991), are currently limited by potential bacterial contamination.
Several methods have been reported for the inactivation or elimination of viral agents in erythrocyte-free blood products. Some of these techniques, such as heat (Hilfenhous, J., et al., J. Biol. Std. 70:589 (1987)), solvent/detergent treatment (Horowitz, B., et al., Transfusion 25:516 (1985)), gamma-irradiation (Moroff, G., et al., Transfusion 26:453 (1986)), UV radiation combined with beta propriolactone, (Prince A. M., et al., Reviews of Infect Diseases 5:92-107 (1983) Prince A. M., et al., Reviews of Infect Diseases 5:92-107 (1983)), visible laser light in combination with hematoporphyrins (Matthews J. L., et al., Transfusion 28:81-83 (1988): North J., et al., Transfusion 32:121-128 (1992)), use of the photoactive dyes aluminum phthalocyananine and merocyanine 540 (Sieber F., et al. Blood 73:345-350 (1989); Rywkin S., et al., Blood 78 (Suppl 1):352a (Abstract) (1991)) or UV alone (Proudouz, K. N., et al., Blood 70:589 (1987)) are completely incomparable with maintainance of platelet function.
Other methods inactivate viral agents by using known furocoumarins, such as psoralens, in the presence of ultra-violet light. Psoralens are tricyclic compounds formed by the linear fusion of a furan ring with a coumarin. Psoralens can intercalate between the base pairs of double-stranded nucleic acids, forming covalent adducts to pyrimidine bases upon absorption of long wave ultraviolet light (UVA). G. D. Cimino et al., Ann. Rev. Biochem. 54:1151 (1985); Hearst et al., Quart. Rev. Biophys. 17:1 (1984). If there is a second pyrimidine adjacent to a psoralen-pyrimidine monoadduct and on the opposite strand, absorption of a second photon can lead to formation of a diadduct which functions as an interstrand crosslink. S. T. Isaacs et al., Biochemistry 16:1058 (1977); S. T. Isaacs et al., Trends in Photobiology (Plenum) pp. 279-294 (1982); J. Tessman et al., Biochem. 24:1669 (1985); Hearst et al., U.S. Pat. Nos. 4,124,598, 4,169,204, and 4,196,281, hereby incorporated by reference.
The covalently bonded psoralens act as inhibitors of DNA replication and thus have the potential to stop the replication process. Due to this DNA binding capability, psoralens are of particular interest in relation to solving the problems of creating and maintaining a safe blood supply. Some known psoralens have been shown to inactivate viruses in some blood products. H. J. Alter et al., The Lancet (ii:1446) (1988); L. Lin et al., Blood 74:517 (1989) (decontaminating platelet concentrates); G. P. Wiesehahn et al., U.S. Pat. Nos. 4,727,027 and 4,748,120, hereby incorporated by reference, describe the use of a combination of 8-methoxypsoralen (8-MOP) and irradiation. P. Morel et al., Blood Cells 18:27 (1992) show that 300 xcexcg/mL of 8-MOP together with ten hours of irradiation with ultraviolet light can effectively inactivate viruses in human serum. Similar studies using 8-MOP and aminomethyltrimethyl psoralen (AMT) have been reported by other investigators. Dodd R. Y, et al., Transfusion 31:483-490 (1991): Margolis-Nunno, H., et al., Thromb Haemostas 65:1162 (Abstract) (1991). Indeed, the photoinactivation of a broad spectrum of microorganisms was been established, including HBV, HCV, and HIV. [Hanson C. V. Blood Cells: 18:7-24 (1992); Alter, H. J., et al., The Lancet ii:1446 (1988); Margolis-Nunno H. et al., Thromb Haemostas 65:1162 (Abstract) (1991).]
Psoralen photoinactivation is only feasible if the ability of the psoralen to inactivate viruses is sufficient to ensure a safety margin in which complete inactivation will occur. On the other hand, the psoralen must not be such that it will cause damage to blood cells. Previous compounds and protocols have necessitated the removal of molecular oxygen from the reaction before exposure to light, to prevent damage to blood products from oxygen radicals produced during irradiation. See L. Lin et al., Blood 74:517 (1989); U.S. Pat. No. 4,727,027, to Wiesehahn. This is a costly and time consuming procedure.
Finally, some commonly known compounds used in PCD cause undesirable mutagenic effects which appears to increase with increased ability to kill virus. In other words, the more effective the known compounds are at inactivating viruses, the more mutagenic the compounds are, and thus, the less useful they at any point in an inactivation system of products for in vivo use. A new psoralen compound is needed which displays improved ability to inactivate pathogens and low mutagenicity, thereby ensuring safe and complete inactivation of pathogens in blood decontamination methods.
The present invention provides new psoralens and methods of synthesis of new psoralens having enhanced ability to inactivate pathogens in the presence of ultraviolet light which is not linked to mutagenicity. The present invention also provides methods of using new and known compounds to inactivate pathogens in health related products to be used in viva and in vitro, and particularly, in blood products and blood products in synthetic media.
With respect to new compounds, the present invention contemplates psoralen compounds, comprising a) a substituent R1 on the 4xe2x80x2 carbon atom selected from the group comprising: xe2x80x94(CH3)uxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)zxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)zxe2x80x94NH2, and xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)yxe2x80x94R4xe2x80x94(CH2)zxe2x80x94NH2; wherein R2, R3, and R4 are independently selected from the group comprising O and NH, in which u is a whole number from 1 to 10, w is a whole number from 1 and 5, x is a whole number from 2 and 5, y is a whole number from 2 and 5, and z is a whole number from 2 and 6; and b) substituents R5, R6, and R7 on the 4, 5xe2x80x2, and 8 carbon atoms respectively, independently selected from the group comprising H and (CH2)vCH3, where v is a whole number from 0 to 5; or a salt thereof. Where an element is xe2x80x9cindependently selectedxe2x80x9d from a group, it means that the element need not be the same as other elements chosen from the same group.
The invention contemplates specific compounds of the above structure, wherein R1 is xe2x80x94CH2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94NH2, and wherein R5, R6, and R7 are all CH3, wherein R1 is xe2x80x94CH2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94NH2, and R5, R6, and R7 are all CH3, wherein R1 is xe2x80x94CH2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94NHxe2x80x94(CH2)4xe2x80x94NH2, and R5, R6, and R7 are all CH3, wherein R1 is CH2xe2x80x94NHxe2x80x94(CH2)4xe2x80x94NH2, and R5, R6, and R7 are all CH3, and wherein R1 is CH2xe2x80x94NHxe2x80x94(CH2)3xe2x80x94NHxe2x80x94(CH2)4xe2x80x94NHxe2x80x94(CH2)3xe2x80x94NH2, and R5, R6, and R7 are all CH3.
The present invention also contemplates psoralen compounds, comprising: a) a substituent R1 on the 5xe2x80x2 carbon atom, selected from the group comprising: xe2x80x94(CH2)uxe2x80x94NH2xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)zxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)zxe2x80x94NH2, and xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)yxe2x80x94R4xe2x80x94(CH2)zxe2x80x94NH2; wherein R2, R3, and R4 are independently selected from the group comprising O and NH, and in which u is a whole number from 1 to 10, w is a whole number from 1 to 5, x is a whole number from 2 to 5, y is a whole number from 2 to 5, and z is a whole number from 2 to 6; and, b) substituents R5, R6, and R7 on the 4, 4xe2x80x2, and 8 carbon atoms respectively, independently selected from the group comprising H and (CH2)vCH3 where v is a whole number from 0 to 5, and where when R1 is xe2x80x94(CH2)uxe2x80x94NH2, R6 is H; or a salt thereof. The present invention contemplate a specific compound having the above structure, wherein R1 is xe2x80x94CH2xe2x80x94NHxe2x80x94(CH2)4xe2x80x94NH2, and R5, R6, and R7 are all CH3.
The present invention also contemplates psoralen compounds, comprising: a) a substituent R1 on the 5xe2x80x2 carbon atom, selected from the group comprising: xe2x80x94(CH2)uxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)zxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)zxe2x80x94NH2, and xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)yxe2x80x94R4xe2x80x94(CH2)zxe2x80x94NH2; wherein R2, R3, and R4 are independently selected from the group comprising O and NH, and in which u is a whole number from 3 to 10, w is a whole number from 1 to 5, x is a whole number from 2 to 5, y is a whole number from 2 to 5, and z is a whole number from 2 to 6; and, b) substituents R5, R6, and R7 on the 4, 4xe2x80x2, and 8 carbon atoms respectively, independently selected from the group comprising H and (CH2)vCH3, where v is a whole number from 0 to 5; or a salt thereof. The present invention contemplates a specific compound having the above structure, wherein R1 is xe2x80x94CH2xe2x80x94NHxe2x80x94(CH2)4xe2x80x94NH2, and R5, R6, and R7 are all CH3.
With respect to methods for synthesizing new compounds substituted at the 4xe2x80x2 position of the psoralen, the present invention contemplates a method of synthesizing 4xe2x80x2-(w-amino-2-oxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen, comprising the steps: a) providing 4xe2x80x2-(w-hydroxy-2-oxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen; b) treating 4xe2x80x2-(w-hydroxy-2-oxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen with a base and methanesulfonyl chloride so that 4xe2x80x2-(w-methanesulfonyloxy-2-oxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen is produced; c) treating 4xe2x80x2-(w-methanesulfonyloxy-2-oxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen with sodium azide, so that 4xe2x80x2-(w-azido-2-oxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen is produced, and d) reducing 4xe2x80x2-[(w-azido-2-oxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen so that 4xe2x80x2-[(w-amino-2-oxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen is produced.
The present invention further contemplates a method of synthesizing a compound of the structure which has a substituent R1 on the 4xe2x80x2 position of the psoralen, described above, where R1 comprises xe2x80x94(CH2)xe2x80x94Oxe2x80x94(CH2)xxe2x80x94Oxe2x80x94(CH2)zxe2x80x94NH2, where x=z, comprising the steps: a) providing a 4xe2x80x2-halomethyl-4,5xe2x80x2,8-trimethylpsoralen selected from the group comprising 4xe2x80x2-chloromethyl-4,5xe2x80x2,8-trimethylpsoralen, 4xe2x80x2-bromomethyl-4,5xe2x80x2,8-trimethylpsoralen, and 4xe2x80x2-iodomethyl-4,5xe2x80x2,8-trimethylpsoralen; b) treating said 4xe2x80x2-halomethyl-4,5xe2x80x2,8-trimethylpsoralen with HO(CH2)xO(CH2)zOH so that 4xe2x80x2-(w-hydroxy-2,n-dioxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen is produced, where n=x+3; c) treating said 4xe2x80x2-(w-hydroxy-2,n-dioxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen with a base and methanesulfonyl chloride so that 4xe2x80x2-(w-methanesulfonyloxy-2,n-dioxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen is produced; d) treating 4xe2x80x2-(w-methanesulfonyloxy-2,n-dioxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen with sodium azide so that 4xe2x80x2-(w-aziduo-2,n-dioxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen is produced; and e) reducing 4xe2x80x2-(w-azido-2,n-dioxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen so that 4xe2x80x2-(w-amino-2,n-dioxa)alkyl-4,5xe2x80x2,8-trimethylpsoralen is produced.
The present invention also contemplates a method of synthesizing 4xe2x80x2-(12-amino-8-aza-2,5-dioxa)dodecyl-4,5xe2x80x2,8-trimethylpsoralen, comprising the steps: a) providing a 4xe2x80x2-halomethyl-4,5xe2x80x2,8-trimethylpsoralen, selected from the group comprising 4xe2x80x2-chloromethyl-4,5xe2x80x2,8-trimethylpsoralen, 4xe2x80x2-bromomethyl-4,5xe2x80x2,8-trimethylpsoralen, and 4xe2x80x2-iodomethyl-4,5xe2x80x2,8-trimethylpsoralen; b) treating said 4xe2x80x2-halomethyl-4,5xe2x80x2,8-trimethylpsoralen with diethylene glycol so that 4xe2x80x2-(7-hydroxy-2,5-dioxa)heptyl-4,5xe2x80x2,8-trimethylpsoralen is produced; c) treating 4xe2x80x2-(7-hydroxy-2,5-dioxa)heptyl-1,5xe2x80x2,8-trimethylpsoralen with a base and methanesulfonyl chloride so that 4xe2x80x2-(7-methanesulfonyloxy-2,5-dioxa)heptyl-4,5xe2x80x2,8-trimethylpsoralen is produced; d) treating 4xe2x80x2-(7-methanesulfonyloxy-2,5-dioxa)heptyl-4,5xe2x80x2,8-trimethylpsoralen with 1,4-diaminobutane so that 4xe2x80x2-(12-amino-8-aza-2,5-dioxa)dodecyl-4,5xe2x80x2,8-trimethylpsoralen is produced.
The present invention contemplates a method of synthesizing 4xe2x80x2-(w-amino-2-aza)alkyl-4,5xe2x80x2,8-trimethylpsoralen, comprising: a) providing 4xe2x80x2-halomethyl-4,5xe2x80x2,8-trimethylpsoralen, selected from the group comprising 4xe2x80x2-chloromethyl-4,5xe2x80x2,8-trimethylpsoralen, 4xe2x80x2-bromomethyl-4,5xe2x80x2,8-trimethylpsoralen, and 4xe2x80x2-iodomethyl-4,5xe2x80x2,8-trimethylpsoralen; b) treating said 4xe2x80x2-halomethyl-4,5xe2x80x2,8-trimethylpsoralen with 1,w-aminoalkane to produce 4-(w-diamino-2-aza)alkyl-4,5xe2x80x2,8-trimethylpsoralen.
The present invention additionally contemplates a method of synthesizing 4xe2x80x2-(14-amino-2,6,11-triaza)tetradecyl-4,5xe2x80x2,8-trimethylpsoralen, comprising: a) providing 4,5xe2x80x2,8-trimethylpsoralen-4xe2x80x2-carboxaldehyde; b) treating 4,5xe2x80x2,8-trimethylpsoralen-4xe2x80x2-carboxaldehyde with spermine and a reducing agent to produce 4xe2x80x2-(14-amino-2,6,11-triaza)tetradecane-4,5xe2x80x2,8-trimethylpsoralen.
Finally, the present invention contemplates the following method of synthesizing 5xe2x80x2-(w-amino-2-aza)alklyl-4,4xe2x80x2,8-trimethylpsoralen comprising: a) providing a 5xe2x80x2-halomethyl-4,4xe2x80x2,8-trimethylpsoralen, selected from the group comprising 5xe2x80x2-chloromethyl-4,4xe2x80x2,8-trimethylpsoralen, 5xe2x80x2-bromomethyl-4,4xe2x80x2,8-trimethylpsoralen, and 5xe2x80x2-iodomethyl-4,4xe2x80x2,8-trimethylpsoralen; b) treating said 5xe2x80x2-halomethyl-4,4xe2x80x2,8-trimethylpsoralen with a 1,w-diaminoalkane to produce 5xe2x80x2-(w-amino-2-aza)alkyl-4,4xe2x80x2,8-trimethylpsoralen.
The present invention contemplates methods of inactivating microorganisms in blood preparations, comprising, in the following order: a) providing, in any order, i) a compound from the group comprising 4xe2x80x2-primaryamino-substituted psoralens and 5xe2x80x2-primaryamino-substituted psoralens; ii) photoactivating means for photoactivating said compounds; and iii) a blood preparation suspected of being contaminated with a pathogen having nucleic acid; b) adding said compound to said blood preparation; and c) photoactivating said compound, so as to inactivate said pathogen.
The pathogen can be single cell or multicellular organisms, such as bacteria, fungi, mycoplasma and protozoa, or viruses. The pathogen can comprise either DNA or RNA, and this nucleic acid can be single stranded or double stranded. In one embodiment, the blood preparation is either platelets or plasma.
The present invention contemplates that the photoactivating means comprises a photoactivation device capable of emitting a given intensity of a spectrum of electromagnetic radiation comprising wavelengths between 180 nm and 400 nm, and in particular, between 320 nm and 380 nm. It is preferred that the intensity is between 1 and 30 mW/cm2 (e.g., between 10 and 20 mW/cm2) and that the mixture is exposed to this intensity for between one second and thirty minutes (e.g., ten minutes).
The present invention contemplates embodiments wherein said blood preparation is in a synthetic media. In one embodiment, the concentration of compound is between 1 and 250 xcexcM. In a preferred embodiment, the compound is added to said blood preparation at a concentration of between 10 and 150 xcexcM.
The present invention contemplates embodiments of the methods where inactivation is performed without limiting, the concentration of molecular oxygen. Furthermore, there is no need for the use of cosolvents (e.g., dimethyl sulphoxide (DMSO)) to increase compound solubility.
In one embodiment, the present invention contemplates methods of inactivating microorganisms in blood preparations, wherein the compound is a 4-primaryamino-substituted psoralen, comprising: a) a substituent R1 on the 4xe2x80x2 carbon atom, selected from the group comprising: xe2x80x94(CH2)uxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)zxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)zxe2x80x94NH2, and xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)yxe2x80x94R4xe2x80x94(CH2)zxe2x80x94NH, wherein R2, R3, and R4 are independently selected from the group comprising O and NH, in which u is a whole number from 1 to 10, w is a whole number from 1 to 5, x is a whole number from 2 to 5, y is a whole number from 2 to 5, and z is a whole number from 2 to 6; and b) substituents R5, R6, and R7 on the 4, 5xe2x80x2, and 8 carbon atoms respectively, independently selected from the group comprising H and (CH2)vCH3, where v is a whole number from 0 to 5; or a salt thereof.
Alternatively, the present invention contemplates embodiments of the method of inactivation, wherein the compound is a 5xe2x80x2-primaryamino-substituted psoralen comprising: a) a substituent R1 on the 5xe2x80x2 carbon atom, selected from the group comprising: xe2x80x94(CH2)uxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)zxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)zxe2x80x94NH2, and xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)yxe2x80x94R4xe2x80x94(CH2)zxe2x80x94NH2; wherein R2, R3, and R4 are independently selected from the group comprising O and NH, and in which u is a whole number from 1 to 10, w is a whole number from 1 to 5, x is a whole number from 2 to 5, y is a whole number from 2 to 5, and z is a whole number from 2 to 6; and, b) substituents R5, R6, and R7 on the 4, 4xe2x80x2, and 8 carbon atoms respectively, independently selected from the group comprising H and (CH2)vCH3, where v is a whole number from 0 to 5, and where when R1 is selected from the group comprising xe2x80x94(CH2)uxe2x80x94NH2, R6 is H; or a salt thereof.
Alternatively, the present invention contemplates embodiments of the method of inactivation, wherein the compound is a 5xe2x80x2-primaryamino-substituted psoralen comprising: a) a substituent R1 on the 5xe2x80x2 carbon atom, selected from the group comprising: xe2x80x94(CH2)uxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)zxe2x80x94NH2, xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)zxe2x80x94NH2, and xe2x80x94(CH2)wxe2x80x94R2xe2x80x94(CH2)xxe2x80x94R3xe2x80x94(CH2)yxe2x80x94R4xe2x80x94(CH2)zxe2x80x94NH2; wherein R2, R3, and R4 are independently selected from the group comprising O and NH, and in which u is a whole number from 3 to 10, w is a whole number from 1 to 5, x is a whole number from 2 to 5, y is a whole number from 2 to 5, and z is a whole number from 2 to 6; and, b) substituents R5, R6, and R7 on the 4, 4xe2x80x2, and 8 carbon atoms respectively, independently selected from the group comprising H and (CH2)vCH3 where v is a whole number from 0 to 5; or a salt thereof.
In one embodiment of the method of inactivation, at least two of the compounds are present. The present invention contemplates embodiments where the compound is introduced either in solution, such as water, saline, or a synthetic media, or in a dry formulation. The present invention also contemplates that the nucleic acid may be DNA or RNA, single stranded or double stranded.